形变时效对Fe14Mn5Si8Cr4NiC形状记忆合金记忆效应和耐蚀性能的影响

Effect of Deforming Aging on the Shape Memory Effect and Corrosion Resistance of Fe14Mn5Si8Cr4NiC Shape Memory Alloy

研究了形变时效对Fe14Mn5Si8Cr4NiC合金形状记忆效应和耐蚀性能的影响.结果表明,对合金进行拉伸变形后时效,碳化物在晶粒内有方向性地大量析出,碳化物的尺寸比未形变时效的更小,分布更均匀,因而有利于提高合金强度,抑制不可逆塑性变形的发生,有利于应力诱发形成薄片状的ε马氏体,使合金的形状记忆效应显著提高,且大变形量要比小变形量的效果显著.对于不同的预拉变形量,最佳时效时间均为300 min左右.对合金进行10%拉伸变形后,形状回复率η比直接时效的合金提高了45%～135%左右,比在最佳淬火温度淬火后的合金提高5%～24%左右.通过电化学腐蚀试验可知,合金变形后时效的耐蚀性能也比较好,接近于18-8型不锈钢.

The influence of deforming aging on the shape memory effect and corrosion resistance of Fe14Mn5Si8Cr4NiC alloy was investigated. The results show that after deforming aging, the numerous fine carbides separate out directionally from grains and distribute evenly, thus this can improve the strength of the alloy, restrain the irreversible plastic deformation and accelerate the stress-induced formation of lamellar ε-martensite, so the shape memory effect of the alloy is enhanced remarkably. Also the effect of big deformation is more obvious than that of the small one. The optimum aging time is about 300 min for different deformation. The shape recovery ratio η of the alloy with 10% deformation increases 45% ～ 135% than that of the alloy without deformation and increases 5% ～ 24% than that of the alloy quenched at the optimum quenching temperature. And meanwhile, the electrochemical corrosion experiment shows that the corrosion resistance of the alloy with 10% deformation is as good as 18-8 stainless steel.